shotleybuilder

shotleybuilder

Exploring Graphs with Elixir: service contexts p.92-93

The book states “define the function graph_service/0 within the body of the using/1 macro
in the GraphCommons.Graph module”

The code download shows this:

defmacro using(opts) do
graph_type = Keyword.get(opts, :graph_type)
graph_module = Keyword.get(opts, :graph_module)

quote do

  # other (listings, new_graph) functions here

  def read_graph(graph_file),
    do: GraphCommons.Graph.read_graph(graph_file, unquote(graph_type))

  def write_graph(graph_data, graph_file),
    do: GraphCommons.Graph.write_graph(graph_data, graph_file,
    unquote(graph_type))
end

end

def graph_service(), do: unquote(graph_module)

def gs() do
graph_service()
graph_info()
end

I’ve not been able to work through the error here and obtain the result shown in the book, namely:

iex> graph_service PropertyGraph
PropertyGraph

So, no solution from me, but I sense there’s more than a one problem here

First Post!

shotleybuilder

shotleybuilder

Okay, this was simply a case of moving
def graph_service(), do: unquote(graph_module)
into the macro.

The error is in the code download

Where Next?

Popular Pragmatic Bookshelf topics Top

edruder
I thought that there might be interest in using the book with Rails 6.1 and Ruby 2.7.2. I’ll note what I needed to do differently here. ...
New
jdufour
Hello! On page xix of the preface, it says there is a community forum "… for help if your’re stuck on one of the exercises in this book… ...
New
mikecargal
Title: Hands-on Rust: question about get_component (page 295) (feel free to respond. “You dug you’re own hole… good luck”) I have somet...
New
raul
Hi Travis! Thank you for the cool book! :slight_smile: I made a list of issues and thought I could post them chapter by chapter. I’m rev...
New
HarryDeveloper
Hi @venkats, It has been mentioned in the description of ‘Supervisory Job’ title that 2 things as mentioned below result in the same eff...
New
jgchristopher
“The ProductLive.Index template calls a helper function, live_component/3, that in turn calls on the modal component. ” Excerpt From: Br...
New
digitalbias
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64) If you follow the defau...
New
taguniversalmachine
It seems the second code snippet is missing the code to set the current_user: current_user: Accounts.get_user_by_session_token(session["...
New
andreheijstek
After running /bin/setup, the first error was: The foreman' command exists in these Ruby versions: That was easy to fix: gem install fore...
New
New

Other popular topics Top

AstonJ
If it’s a mechanical keyboard, which switches do you have? Would you recommend it? Why? What will your next keyboard be? Pics always w...
New
DevotionGeo
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
New
Exadra37
Please tell us what is your preferred monitor setup for programming(not gaming) and why you have chosen it. Does your monitor have eye p...
New
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
New
AstonJ
In case anyone else is wondering why Ruby 3 doesn’t show when you do asdf list-all ruby :man_facepalming: do this first: asdf plugin-upd...
New
rustkas
Intensively researching Erlang books and additional resources on it, I have found that the topic of using Regular Expressions is either c...
New
PragmaticBookshelf
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
New
AstonJ
Was just curious to see if any were around, found this one: I got 51/100: Not sure if it was meant to buy I am sure at times the b...
New
CommunityNews
Last week, a tweet went viral showing a guy claiming that a Cursor/Claude agent deleted his company’s production database. We watched fro...
New

Sub Categories: